Islet isolation from human pancreata for clinical treatment of type 1 diabetes requires bacterial enzymes such as collagenase, thermolysin, and neutral protease to digest the organ and to free the islets from exocrine tissues. However, the quality of collagenase in terms of variability between manufacturers and from lot to lot is a major problem that limits the use of islet transplantation. Thus, there is a need to develop precise and sensitive substrates to evaluate and quantify the activity of bacterial proteases that are critical for the digestion of pancreata to free islets without compromising their quality or quantity. Bacterial proteases are not only relevant for pancreas digestion and enhanced isolation of islets, but also for other tissue dissociation, cell isolation, and cell detachment applications, such as those used to isolate primary cells and stem cells. Therefore, specific and sensitive substrates to assess the activity of certain bacterial proteases may also be useful for isolating primary cells and stem cells. Additionally, these specific and sensitive substrates would also be useful in measuring the activity of bacterial proteases, such as collagenase, which may be used in certain drugs to treat diseases such as those that involve an excess of inelastic collagen (see, e.g., U.S. Pat. No. 5,589,171). Thus, there is a need for specific and sensitive substrates to measure the activity of bacterial proteases, so that appropriate dosage, concentration and/or activity can be determined and used for specific in vitro and in vivo applications.